case 621b

[superdutyII]

I have a case 621b the problem is that the trans. has stopped working the loader pulls fine then it stops just like you put it neutral or pull emegency brake. I checked fluid and checked hand brake switch. Sometimes you can turn it off and crank it back up and it will start working again. I dont have a manual and I was wondering if anyone could help me troubleshoot the problem.

 

[alrman]

Welcome to HEF superdutyII!
Is the brake pressure light on when the problem is there?
Will the machine free wheel when problem is present or is it locked up?

 

[superdutyII]

the light is not on and its free wheeling acts like its in neatral. if i apply hand brake and put it in gear the buzzer goes off letting you know the hand brake is on.

 

[alrman]

Some machines have mechanical de-clutch switches mounted above brake pedals & some have hydraulic ones under the floor, in the articulation area - these need to be checked.
If they test OK, resistance tests need to be carried out on solonoids at the trans. control valve as these often cause problems. You could go through whole testing proceedure but it's quicker to go straight to solonoids & see if they are good.

Some older threads covering this - https://www.heavyequipmentforums.com/showthread.php?18509-621b-case-loader&highlight=case+21
https://www.heavyequipmentforums.com/showthread.php?5555-621B-drive-problem&highlight=case+21
https://www.heavyequipmentforums.co...!!!-Case-621b-trans-problem&highlight=case+21

 

[superdutyII]

what supplies fire to selonoid pack and if its a relay where would it be located

 

[zfrepair]

more than likely a problem in the valve had an old 621 with a plud missing the valve acted the same way

 

[alrman]

For what it is worth - fuses & relays are located behind a panel on RHS of operators seat. Dash may need to removed as well.
If alarm sounds when park brake is on & gear selected - you have power at the FNR controller..... BTW does back up alarm sound in reverse?

 

[quackattak]

Another way I have found to check if a solenoid is the the problem, behind right side of the seat, behind a panel is the trans computer. When you turn key on, the computer will "click" twice. If there is a third "click" the computer is shutting back off because it sense's a open circuit. The two we have the problem has always been a bad solenoid, but could be a bad wire also.

 

[superdutyII]

the back up alarm does work in reverse can you tell me how to check the solenoid

 

[superdutyII]

I screwed the plug loose at the solenoids and checked for fire to the plug and I dont have any fire. what supplies fire to the solenoids

 

[quackattak]

the computer runs the solenoids

 

[offrdrcr]

just replaced the wiring harness on a 621b, the ground wire going to the trans connector was open

 

[superdutyII]

621b

I have power to trans computer but I don't have any coming out. I ordered new trans computer waiting on it to come in

 

[GaryHoff]

Usually the cpu is good (seems to be rather tough) As mentioned before, check the tcu for clicks, 2 is normal a 3rd is it shutting itself down due to a problem. Check the resistance of all your solonoids (i believe spec is around 100-115 ohms) If any of your solonoids resistances are too high or low the controller will shut itself off. Also check all your grounds. The harnessess get old and the grounds get poor. Check the one from your cab to frame, rh side, and there are some below the instrument pannel. Also check your connectors to your solonoids, ensure they are clean (the connector from the cab to the solonoids)

Does your machine have auto shift??

Check your speed sensor, (one is on the LH side, and if you have auto shift the other will be on the RH side top) Sometimes the wires rott off, or the sensor is bad. spec is 1350 to 1590 ohms. A bad speed sensor will prevent you from having 3rd and 4th

A problem in the declutch will prevent you from having 1st and 2nd. You need power to the controller at the declutch wire (i dont remember the wire number right now)

 

[Deerescaper]

721b electrical issues

I have a 97 721b loader giving me fits. I had our local Case Titan dealer out on 2 separate service call and also about 10 hours in their shop diagnosing the problem. I told them to check the solenoids first thing and they said we've never had one go bad before so they *** around looking at everything else first before they checked solenoids and found the top one out. The guy I bought the unit from had changed the top and second one in February and I've only put 120 hours on the loader since then. What should cause a solenoid to go out that quick?? My condition now is I can't keep the 5 amp fuse from blowing. Sometimes it will run 5-6 hours without a problem;then the next time the fuse blows every few changes of direction. Titan checked grounds and harnesses with their box and didn't find any opens or shorts,but there obviously has to have something putting that much electric load to knock out the fuses. Got so pissed today I put a 10 amp fuse in as I ran out of 5's and yes I know that's a no-no as far as computer damage but it even blew a 10 amp out. It is just so inconsistent in behavior that I don't know whether to trust it or not. Any ideas?????

 

[alrman]

It's a longshot Deerscraper, but I had a machine once that had water in a reverse light & kept blowing fuses - took a while to find it, & about 50 fuses!
Might be worth disconnecting reverse lights ( if working) & see how you go.

 

[quackattak]

I fought a 621b that going through a solenoid every month. The ground side on the solenoid wiring harness was open, i pulled the harness apart and tracked the wire back to the connector on the right side of engine. I think there is something else that should ground the solenoids, once I grounded that wire, I never had trouble again. I never have had fuse trouble like your having, solenoid problem the computer will shut itself off. I would check wiring going to computer, also these people might help you, very good about phone support for the ZF. 1-866-792-8220,

 

[superdutyII]

the trans module is clicking 3 times i have checked all grounds and i dont see any problems. any ideas where to go from here

 

[quackattak]

check solenoids with ohm meter, if one is just a little different than others the computer will shut back off. track the ground wire off the solenoids and find where it goes, if the circuit is open it will take out your solenoids.

 

[superdutyII]

all solenoids checked out and i will check grounds again.